1. Field of the Invention
The present invention relates to a vertical articulated industrial robot, especially it relates to an industrial robot adapted to be able be installed very closely between other robots in a production line, having a small height substantially the same level that of works of the production line, and operable within an operating range not exceed the height of the robot during operation, and yet is able to secure a wide operating range including that in the near front side of the robot.
2. Description of the Related Art
A conventional vertical articulated industrial robot, for example, shown schematically in FIG. 4 is proposed which is able to be installed very between other robots in a production line and having a small height substantially the same level that of works of the production line. The height of this robot is made lower than that of the conventional robot. The robot has a fixed base 40, a rotary base 43 mounted on the fixed base rotatably around a vertical swing axis 47, a first arm 44 mounted on the rotary base 43 rotatably around a horizontal first rotational axis 41 closely located to the installation surface 48 of the robot and a second arm 45 mounted on the distal end of first arm 44 rotatably around a horizontal second rotational axis 42. A wrist 46 is mounted at a distal end of the second arm 45.
The robot shown in FIG. 4 has a considerably wide operating range 4A since (slant lines) or working envelop in the near front side as seen in side view. However, referring to FIG. 5, when the first arm 44 and the second arm 45 are folded together during operation, the folded portions projecting into the rear side of the robot forms a range B or space shown in FIG. 6 in a plan view which interfere with the ambient installations. This results that this type of robot is not suitable to be installed very closely between other robots in a production line. In FIG. 6, for easy explanation, the swing angles are expressed as limited within about 120 degrees, and 6A is an operating range of the front side.
To eliminate the interference range such as B shown in FIG. 6, U.S. Pat. No. 5,375,480, for example, discloses a robot shown in FIG. 7 in skeleton. This robot has a fixed base 71, a rotary base 72 mounted on the fixed base rotatably around a vertical swing axis 78, a first arm 73 mounted on the rotary base 72 rotatably around a horizontal first rotational axis 76 located on the outer end of the rotary base 72 positioned substantially above the outer surface of the fixed base 71 and a second arm 74 mounted on the distal end of the first arm 73 rotatably around a horizontal second rotational axis 77. A wrist 75 is mounted at the distal end of the second arm 74. Although the robot shown in FIG. 7 can eliminate the interference range such as shown in FIG. 6, it is however, unable to have a considerably wide operating range 4A as been shown in FIG. 4.